For steel bending lever bar movements are essential, and a tight grip is needed to direct the force. John Brookfield wrote in “Mastery of Hand Strength” on combining a crush grip and a lever bar, and he showed several options. Here is my own lever bar + crush.
The bar was made back in metal shop when i was in school. All i need to do is feed a COC handle in the butt and i am good to go.
Do not start off with your toughest gripper, this drill may humble you…